C0021 — Brake Booster Performance

What Does C0021 Mean?

C0021 is a diagnostic trouble code indicating: Brake Booster Performance. This code relates to the chassis system. It has been reported in NHTSA complaints across 3 different vehicle models.

Common Causes

🔍 Turbocharger or boost system issue

C0021 Reports by Year

2023

2

2026

1

Real Owner Reports

From NHTSA complaint database — actual owner descriptions.

"My 2014 Dodge Durango’s VIN is not listed as impacted by Safety Recall P14/NHTSA 14V-154. However, my vehicle is showing symptoms that match the problem described for that recall. I am requesting an investigation to determine if more VINs than originally impacted are affected by the problem descri"
— Dodge Durango owner, 01/21/2026

"I received P258B warning and further diagnosis came to know that C0021-02 and C1252-92 warnings. While applying breaks i am getting hissing noise and break pedal pushes me back where i have to apply lot of pressure to stop the vehicle. This is happening only when i press the pedals hard. I did diag"
— Chrysler Pacifica owner, 07/06/2023

"Upon inspection, Power Brake Booster failure, my safety is at Risk due to not having brakes, the issue it has been a confirmed in older models from 2013-2014, recall R63, it has been inspected by an expert and a message pops saying Service Electronic Brake System with code C0021"
— Dodge Dart owner, 03/13/2023

Source: NHTSA Complaints Database

Most Reported Vehicles for C0021

Based on NHTSA owner complaint data.

#	Vehicle	Reports
1	DODGE DURANGO
2	DODGE DART
3	CHRYSLER PACIFICA

Frequently Asked Questions

Can I drive with this code?

It depends on the severity. If the vehicle runs normally, short trips are usually OK. If you notice performance issues, drivability problems, or warning lights beyond the check engine light, get it checked soon.

Will this code clear itself?

Some codes clear automatically after the underlying issue is fixed and several drive cycles pass. But the root cause must be addressed first.

How do I find the exact cause?

A code alone doesn't pinpoint the failed part. You need a diagnostic scan ($50-150 at most shops) that reads freeze frame data and live sensor readings to identify the specific component.

What To Do Next

Possible Fixes

🔧 Have the code scanned with a professional-grade scanner to read freeze frame data
🔧 If DIY repair isn't feasible, get a diagnostic from a trusted mechanic ($50-150)

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

C0021: Brake Booster Performance